Field of the Invention
The present invention relates generally to a method and apparatus for delivering multimedia data packets in a broadcasting and communication system, and more particularly, to a method and apparatus for delivering transport characteristics of multimedia data in units of Media Processing Unit (MPU) groups for Quality of Service (QoS) control when multimedia content constituted with one or more MPUs is serviced in a network environment dynamically changing over time in a broadcasting and communication system that supports a multimedia service based on an Internet protocol.
Description of the Related Art
IEEE802.16 (WIMAX), IEEE802.11e (WiFi TXOP), 3rd Generation Partnership Project Universal Mobile Telecommunication System (3GPP UMTS), and 3GPP Long Term Evolution (LTE) have a function of reserving resources and guaranteeing the reserved resources. Real-time multimedia services use a resource reservation protocol in order to guarantee QoS. As a representative example, Internet Engineering Task Force (IETF) has defined parameters required for reserving network resources between user terminals and a content server in a Resource reSerVation Protocol (RSVP) which is a resource reservation protocol.
FIG. 1 illustrates a process of specifying data with a Variable BitRate (VBR) as double leaky bucket parameters.
VBR traffic is expressed as double leaky buckets using four parameters Rg, Rp, Bp, and B included in Traffic specification Tspec. Rg is an average bitrate, and no overflow occurs when data is stored in a buffer although the bitrate of the data momentarily exceeds the bitrate Rg. A required buffer size is designated as Bg in advance. Likewise, a peak bitrate Rp is also reserved. Under an assumption that a peak bitrate is maintained during a period in which a packet is transported, a buffer size Bp for a peak bitrate Rp can be set to the maximum size of Service Data Unit (SDU). The maximum size of SDU is generally expressed as Maximum Transfer Unit (MTU).
Table 1 shows four double leaky bucket parameters used in various protocols.
TABLE 13GPPIETF RSVP,UMTSIEEE802.11eIEEE802.16&‘tspec’(WIMAX)LTEMPEG-4 ODATMRppMin.Maxi-avgBitratePCRreservedmumtraffic ratebit-rate(4B)BpMSDU sizeMaxiMAX_AU_SIZECDVTmumSDUsizeRgrMax.Guar-AverageBitRateSCRsustainedanteedtraffic ratebit-rate(4B)BgbMaximumk *bufferSizeDBBTLatencyMaxi-mumSDU
Accordingly, creating transport characteristics of multimedia using double leaky bucket parameters is effective in view of compatibility with other protocols. Generally, the resource reservation protocol is executed when a service session for providing a multimedia service is established, and it is assumed that while a service is maintained, the protocol is used by end-to-end systems on a network that transports data with respect to entire multimedia content. However, end-to-end resource reservation for a service cannot be embodied in general open Internet environments. Furthermore, a core network achieves stable broadband transmission, however, at or near network end points, a problem may occur due to resources sharing between many users. Particularly, in a wireless or mobile communication network, a network resource environment changes dynamically due to various factors, such as users' migration, interference, or the like.
FIG. 2 illustrates Signal to Interference plus Noise Ratio (SINR) measured for 10 minutes in an IEEE802.16 network environment.
The Moving Picture Experts Group (MPEG) is doing standardization of MPEG Media Transport (MMT) technology, and the MMT technology provides transport characteristics in a unit of asset through Asset Delivery Characteristics (ADC) in order to embody a function of reserving a resource for a multimedia service and guaranteeing the reserved resource and a function of constructing transport characteristics of multimedia data in a dynamic network environment and transmitting/receiving the transport characteristics.
In the MMT technology, an asset is logical data entity, and constructed with one or more Media Processing Units (MPUs). The asset is a greatest data unit to which configuration information and transport characteristics of multimedia are applied.
The ADC is used to guarantee QoS upon transmission of MMT assets, and the ADC specifies parameters for a specific transmission environment and parameters for QoS. By using the ADC, a service provider can configure a network resource in consideration of media characteristics required for transmission when reserving a resource according to network environment configuration. However, in a dynamic network environment where SINR varies in real-time, it is difficult to guarantee the amount of resource reserved using existing RSVP or the like when a service session started. Furthermore, in a mobile environment, when a user moves into the coverage area of another base station, resource reservation should be again performed. For these reasons, when a resource is reserved in order to guarantee QoS of a multimedia service in a dynamic network environment, it will be effective to reserve a resource in units of shorter lengths than in resource reservation for entire content. Accordingly, there is a need to propose a method of inserting additional information for controlling QoS for MPUs in a unit of a MPU group including a plurality of MPUs each of which is a small unit constituting media content.